The Ultimate Fighting Championship's longtime king of pay-per-view is gone, at least for now. With welterweight champion Georges St-Pierre vacating his title and stepping away from the sport for an indefinite period, the UFC has a huge void to fill and no clear successor to the throne.

It couldn't come at a trickier time for the largest mixed martial arts promoter. It finishes off 2013 on Dec.28 with what it hopes will be its biggest event of the year in UFC 168, one that will see a one-time increase of $5 in the PPV price, for reasons UFC President Dana White couldn't or wouldn't explain.

It kicks off its new subscription-based digital network in January, which will charge fans a monthly fee to watch lesser-known fighters compete on foreign soil.

Question remain: Who will those fans be paying to see, and what happens if they don't?

If White is worried about it, he isn't saying so. Talking to new reporters early Sunday following UFC on Fox 9 in Sacramento, he dismissed concerns that people wouldn't tune in to see light heavyweight contender Alexander Gustafsson if his next bout streams exclusively on the UFC's digital network.

"When you're doing the things that we're doing, whether it's launching Fox Sports 1 (or) launching a new digital network, you have to have the (guts) to go out there and take your lumps," White said. "... These are the type of things you have to do when you're trying to grow your business and do new things. You have to take risks, and you have to take chances."

For some fighters, the UFC's risks could lead to financial opportunity. With St-Pierre on self-imposed hiatus, there's an opening for a new PPV star to emerge, though capturing the interest of fickle fight fans seems to require a blend of violent skill and natural star power.

UFC flyweight champ Demetrious Johnson proved he had at least one of those attributes with a first-round knockout of challenger Joseph Benavidez, but the lighter-weight fighters have struggled to gain serious traction in the UFC, and the 125-pound Johnson is as light as it gets.

Former middleweight champ Anderson Silva, who attempts to reclaim the title from Chris Weidman at UFC 168, is often hailed as the greatest MMA fighter of all time, but at 38, he is much closer to the end of his career than the beginning.

If the replacement for St-Pierre is waiting on the year-end fight card, it could even be in the form of women's bantamweight champion Ronda Rousey, who has a knack for evoking strong feelings in supporters and detractors. But she also has garnered attention from Hollywood, which has led many fans to wonder how long she'll be content to make her money inside the cage rather than on the movie set.

No one ever said that replacing a star such as St-Pierre would be easy. The UFC has to hope that, however difficult it might be, it's possible.

Then again, as White pointed out, it's not as if St-Pierre walked away because of serious health issues as much as personal life problems.

"Once he fixes it," White said on a recent media call to break the news, "I'm confident he'll come back."